Load-balancing device



July 29, 1 958 K GU D $2,845,263

LOAD-BALANCING DEVICE FiledUuly 1'7, 1952 firzraez nal,

United States Patent LOAD-BALANCING DEVICE Konrad Gund, Erlangen, Germany Application July 17, 1952, Serial No. 299,468

Claims priority, application Germany July 30, 1951 8 Claims. (Cl. 267-1) This invention is concerned with a loador forcecompensation or balancing device having a leverlike load carrier, the weight of the load affecting the carrier with constant force.

The device may be used, for example, with X-ray apparatus in which a load such as an X-ray tube is manually adjusted relative to an object. The load is in such case balanced so that it may be moved without effort.

Details of the invention will appear from the following description which will be rendered with reference to the accompanying diagrammatic drawings wherein:

Fig. 1 shows an embodiment for balancing a load along a perpendicular line; and

Fig. 2 indicates the manner in which the invention may be used in connection with X-ray apparatus.

It is assumed in connection with the embodiment shown in Fig. 1 that a point connecting with a load to be balanced is disposed for displacement along a straight perpendicular line. The invention accomplishes this object by the provision of a lever system linked with spring means. Such system comprises a lever 35 which is pivotally connected at 36 and a lever 37 having a bolt or pin 38 (constituting the load connecting point) disposed for motion within a perpendicular slot 39. The inner ends of the levers 35 and 37 are pivotally linked at M to a double-armed lever 46, to the arms of which are pivotally linked rods 44 and 45, at B and B, respectively, for controlling springs 40 and 41. The springs are confined by bearings or end plates 42, 43 which are respectively pivotally linked with the levers 35 and 37 as indicated at A and A. The forces of the two springs 40, 41 operate through the medium of the rods 44, 45 upon the arms of the lever 46 at points B and B. The lever 46 equalizes the rotary motion caused by the spring forces about a pivot point M so that the lever 46 always retains the identical position. The points B, B accordingly will always be at the same position relative to point M, which is an essential prerequisite for the exact functioning of the device. It is not absolutely necessary that the elements of the device are arranged symmetrically as shown in Fig. 1. The two operation triangles formed by the points A, B, M and A, B', M may be altered relative to one another, as may be desired or required according to operating conditions.

Fig. 2 indicates how the structure shown in Fig. 1 may be used, for example, for balancing the weight of a carriage 47 carrying an X-ray tube and coacting with tiltable table 48 of an X-ray apparatus, in any position of the table. The table 48 is journalled in a stand 49 so that it is tiltable about a horizontal axis 50. The lever device according to Fig. l is secured to a floor carriage 51 which is movable along rails 52 in the direction of the longitudinal axis of the table 48. The lever device extends perpendicular to the rails 52, and the loadconnecting point 53 (corresponding to point 38 in Fig. 1) therefore moves in a perpendicular plane. The straight ice guide of the load-connecting point is eifected by guiding the tube carriage 47 in rails 54, 55 disposed along longitudinal edges of the table. The structure relieves the table 48 of the weight of the X-ray tube and of the tube carriage 47, thus eliminating counterweights which would otherwise be required for balancing these elements. A particular advantage resides in the fact that the elimination of counterweights for the X-ray tube and for the tube carriage relieves the physician engaged in X-ray investigations of having to accelerate these masses or having to apply braking force in making the necessary adjustments.

Changes may be made within the scope and spirit of the appended claims.

I claim:

1. A load balancing device comprising a load lever having one end thereof connected with a load which acts thereupon with constant force exerted in constant direction, means for guiding the corresponding end of said load lever for displacement along a predetermined path, a leverlike member having one end thereof pivotally disposed for angular displacement about a relatively fixed point, an intermediate double-armed lever, common pivot means for inter-linking said double-armed lever midway thereof with the other ends of said load lever and said leverlike member, respectively, a pair of load balancing springs, means for linking corresponding ends of said springs and said load lever and said leverlike member, respectively, and means respectively in engagement with the other end of each spring for transmitting the force thereof to an arm of said double-armed lever.

2. A device as defined in claim 1, wherein said load lever and said leverlike member are for scissorlike displacement symmetrically disposed relative to the pivot axis of said double-armed lever, said load balancing springs being symmetrically disposed with respect to said pivot axis, said predetermined path for guiding the corresponding end of said load lever for displacement extending in a direction corresponding to the direction of force exerted by said load.

3. A device as defined in claim 2, wherein said double-armed lever has two arms of identical length, said arms extending at identical angles with respect to said load lever and said leverlike member.

4. A device as defined in claim 3, comprising compression springs constituting said load balancing springs, one end of each spring being connected with an arm of said double-armed lever and the other ends of said springs being respectively connected with said leverlike member and said load lever at points identically spaced from said common pivot axis.

5. A device as defined in claim 1, comprising means for movably disposing the fixed pivot of said lever-like member, said means for guiding said corresponding end of said load lever being displaceable with the displacement of said common pivot means in identical direction of displacement thereof.

6. In combination with a base member and apparatus movably disposed thereabove, a device for balancing the load of said apparatus, said device comprising means on said base member forming a relatively fixed pivot, means on .said apparatus forming a guide slot positioned above said fixed pivot, levers respectively extending from said guide slot and said fixed pivot, a bearing pivoted to each lever and extending therefrom, means for pivotally joining the free ends of said levers, an angular generallyV- shaped lever pivotally secured at a midpoint thereof upon the pivot joining the free ends of said levers, a rod extending through the respective bearings and pivotally secured 1.01311 end of-said V-shaped lever, and a balancing spring acting between each of said rods and the respective bearing.

7. A structure as defined in claim 6, comprising means carried by each rod for engaging the other end ofthe associatedrspring.

1' 8 A structure defined in claim 6, comprising means for movably mountingsaid base member.

'References'Cited in the file of this patent UNITED STATES PATENTS Dahlstrom June 7, 1921 Wood Nov. 28, 1933 Grabs Sept. 18, 1951 Rouvcrol Oct. 28, 1952 Kohler Nov. 18, 1952 

